Simple UV Exposure Timer

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Simple exposure timer with relay output to control a UV source.

With the realy output pretty much any UV source can be controlled as long as you make sure that the relay is correctly rated for the job.

In my project i use a UV LED pannel, construction of which can be found at
http://www.instructables.com/id/...

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Thank you, was needed an example of how assembled a exposure box... can extend the time to exposure???

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Hi Sax,
the box can be made from the instructable web site, or as i did just knock one up of your own design. The design on the instructable web site shows a double sided design, which is better than mine as mine is only single sided. I simply expose one side at a time.

As for extending the exposure time, change the prescalar value at the top of the uv-timer.c file, currently it is

#define PRESCALAR 100*30

for 30 seconds a segment, change this to 100*60 for 60seconds persegment.

From what i understand, most pre-sesnsitized pcb board only take from 30s to 5mins to expose so thats why chose those the values. Also it divided by 10 for the 10 segment display.

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Here's a simple UV exposure unit I made from MDF and some pieces of square section wood:

http://www.leonheller.com/Photos/UV%20unit.jpg

A sheet of glass rests on the upper wood strips. The wood and MDF are held together with wood screws and adhesive.

I use an exposure time of 11 minutes. I keep meaning to add another UV tube, it should reduce the exposure time to five minutes or so.

Leon

Leon Heller G1HSM